From owner-freebsd-threads@FreeBSD.ORG  Fri Sep 24 08:59:40 2010
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Date: Fri, 24 Sep 2010 10:38:05 +0200
From: Thomas Mueller <tmueller@sysgo.com>
To: John Baldwin <jhb@freebsd.org>
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Cc: freebsd-gnats-submit@freebsd.org, Christopher Faylor <cgf@netapp.com>,
	freebsd-threads@freebsd.org
Subject: Re: threads/150889: PTHREAD_MUTEX_INITIALIZER +
 pthread_mutex_destroy() == EINVAL
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On Thu, 23 Sep 2010 14:14:50 -0400, John Baldwin wrote:
> On Thursday, September 23, 2010 1:33:56 pm Christopher Faylor wrote:
> >   In cases where default mutex attributes are appropriate, the macro
> >   PTHREAD_MUTEX_INITIALIZER can be used to initialize mutexes that are statically 
> >   allocated. The effect shall be equivalent to dynamic initialization by a call to
> >   pthread_mutex_init() with parameter attr specified as NULL, except that no error
> >   checks are performed.
> 
> I suppose that is true, but I think this is also probably buggy code if you
> are doing this.  The use case for PTHREAD_MUTEX_INITALIZER is static
> initialization of static objects to ease adding locking to C libraries where
> constructors are not easy.

Note that future standard text might drop the "statically allocated"
part in the pthread_mutex_init() description, see also
http://www.austingroupbugs.net/view.php?id=70

-- 
Thomas Mueller